1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to a data driving block for an LCD. device.
2. Discussion of the Related Art
The demand for various display devices has increased with the development of an information society. Accordingly, many efforts have been made to research and develop various flat panel display devices such as liquid crystal displays (LCD), plasma display panels (PDP), electroluminescent displays (ELD), and vacuum fluorescent displays (VFD). Some types of flat panel display devices are used as displays in various types of equipment.
Among the various flat display devices, LCD. devices have been the most widely used substitutes for cathode ray tube (CRT) displays because LCD devices have advantageous characteristics of compact size, thin profile, and low power consumption. In addition to use in mobile type devices such as notebook computers, LCD devices have been employed as computer monitors and in televisions to receive and display broadcasting signals.
Hereinafter, a related art LCD device will be explained with reference to FIGS. 1. and 2 of the accompanying drawings.
FIG. 1 is a layout of a related art LCD device. FIG. 2 is a plan view of illustrating a pitch of a data driving block in a related art LCD device.
As shown in FIGS. 1 and 2, a related art LCD device includes a liquid crystal panel 20 that includes lower and upper substrates 11 and 10; a liquid crystal layer disposed between the lower and upper substrates 11 and 10; a gate driving block 12 that includes a plurality of gate drivers disposed at the edge of the lower substrate 11; a data driving block carrier packages (TCPs) 13; and a seal line 16 provided in the margin of the lower and upper substrates 11 and 10 to bond the lower and upper substrates 11 and 10 to each other.
In the above described structure, an integrated circuit (IC) connects the gate driving block 12 to the data driving block 15. The IC may be a flexible printed circuit (FPC) or a chip on film (COF) device. The example illustrated in FIG. 1 includes a gate COF device.
Further, a timing controller (not shown) is provided to supply control signals and video information to the gate driving block 12 and the data driving block 15.
The liquid crystal panel 20 includes a pixel unit 21 for displaying images. The pixel unit 21 includes: a plurality of gate lines perpendicularly crossing a plurality of data lines on the lower substrate 11 to thereby define a matrix of pixel regions; a plurality of pixel electrodes respectively formed in the pixel regions defined by the gate and data lines; and a plurality of thin film transistors formed adjacent to crossings of the gate and data lines for applying a signal on the data line to each pixel electrode in accordance with a signal provided on the gate line.
Each thin film transistor includes a gate electrode protruding from one side of the gate line; a gate insulating layer formed on an entire surface of the lower substrate including the gate electrode; an active layer overlapping the gate electrode; a source electrode overlapping one side of the data line and one side of the gate electrode; and a drain electrode provided at a predetermined interval from the source electrode.
A passivation layer is formed on the lower substrate including the data line and a first contact hole is provided in the passivation layer at a predetermined portion corresponding to the drain electrode. The drain electrode contacts the pixel electrode through the first contact hole in the passivation layer.
Although not shown, the upper substrate 10 includes a color filter layer in each pixel region, a black matrix layer, and a common electrode corresponding to the pixel electrode of the lower substrate 11.
In a LCD device having the above structure, liquid crystal molecules of the liquid crystal layer are driven by a voltage applied to the common and pixel electrodes that generates an electric field between the lower and upper substrate 11 and 10.
The data driving block 15 includes a data pad unit 19 to transmit the data signal from a data chip 18 to a data line of the liquid crystal panel 20.
As shown in FIG. 2, the data pad unit 19 has a constant pitch ‘d’ on each data TCP 18. That is, the data pad unit 19 includes of a plurality of data pads 23 each having the same width and with adjacent data pads 23 spaced apart by a constant interval.
However, when each data TCP 13 of the data driving block 15 is bonded to the pad of the lower substrate 11 where the data pad unit 19 has the same pitch, a misalignment may result from differential expansion of portions of the data pad unit 19.